After keeping my iPhone data/charging cable in the car for too long, I have the problem described here which is that the tiny contacts on the "lightning" end of the cable have become corroded, and the cable no longer works.

I'm not even sure what chemical factors are causing it to happen—moisture, perhaps?—but apparently others have reported that it happens when you leave the cable in your car (which, to save hassle, I would ideally like to do).

Wherever I've seen the issue discussed, the "answer" always seems to be to replace the cable. But these cables are expensive and replacing any physical object on a regular basis is tedious. Is there any kitchen chemistry I can use to remove the corrosion? Or to prevent it from happening in the first place?

Corrosion image from macrumors.com

  • 1
    Return it immediately to Apple. It might be due to manufacturing problems and they should know about it. I would expect they would replace the cable without question as it appears to be in excellent condition lacking any evidence of misuse. Do not do anything to the part before you contact Apple in case you void the warrantee with your "repair." The $25 cord for you costs Apple a few pennies and they won't blink before replacing it.
    – Stan
    Commented Feb 17, 2017 at 20:01
  • This is possibly a duplicate of lifehacks.stackexchange.com/questions/18489/…
    – Stan
    Commented Sep 26, 2018 at 18:28

6 Answers 6


Use a pencil eraser.

People have been cleaning electrical contacts with pencil erasers for as long as there have been contacts that needed cleaning.

Some examples...

enter image description here enter image description here

One thing to note - those metal strips are actually very easy to damage, so don't scrub at them like a dirty stove-top, treat them gently.
Gentle repetition is better than aggressive over-eagerness.

As for prevention...
assuming it's because of moisture getting to it, any oil-based product will help - WD-40, even olive oil, used very sparingly will not adversely affect the conductivity. When inserted into the iDevice socket, the mechanical pressure of the contacts is sufficient to push through the oil layer.

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    Thanks, it helped me to restore 3 out of 4 USB-C cables that I ruined using salt water and baby eating them!
    – dzh
    Commented Sep 10, 2020 at 6:09

Soak it in distilled white vinegar for a few minutes.

Vinegar can be used to remove corrosion. Dip the end of the corroded cable in a small amount of distilled white vinegar for a few minutes. If the corrosion is really bad, the end of the cable may have to be soaked for an hour or more. After removing the end of the cable from the vinegar, baking soda can be used to neutralize any remaining acid. Any remaining corrosion can be removed using steel wool.

I hope that expanded answer is elaborate enough for Just Do It.

  • Could you elaborate please?
    – Just Do It
    Commented Apr 27, 2016 at 21:28
  • Has this worked for you? After an hour in vinegar the contacts don't look much different. (Aren't they gold? How does gold even get corroded in the first place?)
    – jez
    Commented May 1, 2016 at 1:40
  • 1
    I recently used vinegar to clean the battery compartment of an air pump. The batteries had leaked and the chrome plated metal in the compartment was covered with corrosion. The vinegar didn't remove all of the corrosion, but it removed enough that I was able to use the pump. Some steel wool would have removed the rest. Gold doesn't corrode. However, most electrical contacts are only gold plated, not solid gold. If the contacts are corroded, the gold is gone and the underlying metal is what has oxidized.
    – user13676
    Commented May 2, 2016 at 22:14
  • Worked for me -- got most of the corrosion off. Commented Jan 21, 2020 at 20:17

So I had the same problem but didn't realize it

I took a closer look at the usb cord I have - it looked very much like the photos above but a little scummier. So I took an ordinary staple, out of my stapler, and scratched the blackish green stuff off. The cord works again and my phone is charging as it ought to.


I'm cleaning my old iPhone 5c lightning cable pins with a toothbrush (toothpaste + salt) - works fine, as the problem is in fact in demage of iPhone port and black pins will back again after approx. one week.


Black isn't corrosion, it's carbon. The carbon is likely due to arcing. These cords simply don't fit snugly enough and there is arcing during the charge process... this is why the eraser or soaking doesn't remove it.

  • That doesn't make sense to me... They should fit securely because they did work at one time. Also, the black came after the person left the cords in their car for too long, that shouldn't result in arcing unless there was moisture. In which case it shouldn't have already been on the cables when they were removed from the car.
    – L.B.
    Commented Feb 15, 2017 at 20:38

All that is on the metal is carbon deposits from the iPad itself, so don't worry about the entire metal piece corroding.

  • 1
    How does an Ipad generate carbon?
    – Chenmunka
    Commented Apr 19, 2017 at 7:31
  • @Chenmunka Arcing due to an occasionally poor connection, I believe.
    – L.B.
    Commented Apr 19, 2017 at 13:17

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